Diagnostic delay and onset-anchored clinical milestones in progressive supranuclear palsy: a japanese single-center retrospective cohort study.

BACKGROUND

Progressive supranuclear palsy (PSP) causes falls, dysphagia, pneumonia, fractures, and death, but routine-care timelines and diagnostic-delay survival analyses remain limited.

METHODS

We retrospectively studied 68 patients with probable PSP at a Japanese single center. Outcomes were intervals from symptom onset to first visit, probable PSP diagnosis, aspiration pneumonia admission, fracture hospitalization, and death. Patients were grouped by the median onset-to-diagnosis interval (1005.5 days). Survival was analyzed from onset and diagnosis. Sensitivity analyses modeled delay continuously and using 24-, 36-, and 48-month cut-offs; competing risks used Aalen-Johansen estimates.

RESULTS

Screening identified 81 patients; 68 remained after chart review. Median onset-to-first visit and onset-to-diagnosis intervals were 24.8 and 33.0 months. Among observed events, median onset-to-aspiration pneumonia admission and onset-to-death intervals were 58.8 and 62.2 months; median diagnosis-to-death among deceased patients was 27.1 months. Death occurred in 26/68 patients (38.2%). Early and Delayed groups had identical death counts (13/34 each), but onset-origin survival differed (log-rank p=0.0013), whereas diagnosis-origin survival did not (p=0.8657). Sensitivity analyses showed the same onset-origin pattern.

CONCLUSIONS

Diagnostic delay was substantial, and severe outcomes accumulated over several years. Survival differences by delay group depended on time origin, censoring, and residual selection, and should not be interpreted causally. These timelines may support surveillance and anticipatory care planning in PSP.